More than herbivory: levels of silica-based defences in grasses vary with plant species, genotype and location
More than herbivory: levels of silica-based defences in grasses vary with plant species, genotype and location
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DOI：
10.1111/j.1600-0706.2012.20689.x
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发表时间：
2013-01-01
期刊：
影响因子：
3.4
通讯作者：
Hartley, Susan E.
中科院分区：
文献类型：
--
作者：
Soininen, Eeva M.;Brathen, Kari Anne;Hartley, Susan E.
草中的二氧化硅防御最近被认为是田鼠种群动态的潜在驱动力。然而，在小型啮齿动物是重要食草动物的北方生态系统中，草诱导二氧化硅响应食草动物的能力尚未得到测试。我们在亚北极苔原利用三个不同食草动物密度的河流集水区进行了大规模的田间试验，并研究了小型啮齿动物和/或驯鹿排除对五种草的叶片二氧化硅水平的影响（Avenella flexuosa、Anthoxanthum nipponicum、Calamagrostis phragmitoides、Deschampsia cespitosa和Phleum alpinum）。我们还使用其中三个物种进行了温室实验（A。flexuosa，A. nipponicum和D. cespitosa）和高羊茅（Festuca ovina）的研究，以确定种内基因型变异是否影响基线二氧化硅浓度和诱导二氧化硅响应模拟放牧的能力。基线叶片二氧化硅浓度和二氧化硅诱导在两个实验中的植物物种，在田间实验中的集水和在温室实验中的基因型。这些研究结果表明，分配到硅防御草是高度可变的，并建议放牧压力，植物物种和种内基因型差异的综合影响很可能决定的情况下，二氧化硅诱导可能是一个最佳的防御策略。更好地了解放牧和其他因素之间的相互作用，影响二氧化硅诱导是必要的，以解释植物-草食动物相互作用中的作用。
Silica defences in grasses have recently been suggested to be a potential driver of vole population dynamics. However, the ability of grasses to induce silica in response to herbivory has not been tested in northern ecosystems where small rodents are important herbivores.We conducted a large-scale field experiment in subarctic tundra using three river catchments differing in herbivore densities, and examined the effects of small rodent and/or reindeer exclusion on leaf silica levels in five grass species (Avenella flexuosa, Anthoxanthum nipponicum, Calamagrostis phragmitoides, Deschampsia cespitosa and Phleum alpinum). We also conducted a greenhouse experiment using three of these species (A. flexuosa, A. nipponicum and D. cespitosa) and Festuca ovina to determine whether intraspecific genotypic variation affects baseline silica concentrations and the capacity to induce silica in response to simulated grazing. Baseline leaf silica concentrations and silica induction varied with plant species in both experiments, with catchment in the field experiment and with genotype in the greenhouse experiment. These findings show that the allocation to silica defences in grasses is highly variable, and suggest that the combined effects of grazing pressure, plant species and intraspecific genotypic differences are likely to determine the circumstances under which silica induction may be an optimal defence strategy. A better understanding of the interplay between grazing and other factors influencing silica induction is necessary to interpret the role of silica in plant-herbivore interactions.